1. Field of the Invention
The present invention relates to an installation for the rehabilitation of a ballast bed supporting a track including two rails, which comprises a first machine, a second machine, the machines being supported on the track by undercarriages for movement in an operating direction, and the second machine preceding the first machine in the operating direction. A vertically adjustable ballast excavating device is mounted on the first machine for excavating ballast from underneath the track, a first conveyor arrangement is arranged to remove the excavated ballast from the ballast excavating device, a second conveyor arrangement is mounted on the first machine for conveying bulk material, the second conveyor arrangement having a discharge end rearwardly of the ballast excavating device in the operating direction and an input end arranged at an end of the first machine, and a third conveyor arrangement is mounted on the second machine for conveying the bulk material, the input end of the second conveyor arrangement being arranged to receive the bulk material from a discharge end of the third conveyor arrangement.
2. Description of the Prior Art
An ballast bed rehabilitation installation of this type has been disclosed in our copending U.S. patent application Ser. No. 08/036,712, filed Mar. 25, 1993, now U.S. Pat. No. 5,394,944 (which corresponds to German patent application No. 4,312,585, published Nov. 4, 1993). As this installation continuously advances along the track, dirty ballast is excavated by the vertically adjustable ballast excavating device and removed by a first conveyor arrangement to a ballast screening device for cleaning. The cleaned ballast is returned by a second conveyor arrangement and discharged on the subgrade from which the dirty ballast was removed by the ballast excavating device. A third conveyor arrangement is arranged to convey additional clean ballast to the second conveyor arrangement from a storage car of clean ballast in case of need for such additional ballast, either to replace excessive amounts of detritus in the excavated ballast or to increase the height of the ballast bed.
U.S. Pat. No. 5,090,484 discloses a mobile ballast cleaning machine installation which comprises a first machine frame carrying two vertically adjustable ballast excavating devices for excavating dirty ballast from the track shoulders. The excavated ballast is cleaned on a screen arrangement mounted on a second machine frame succeeding the first machine frame in the operating direction, and the cleaned ballast is discharged on the track bed. A third machine frame succeeding the second machine frame in the operating direction carries another ballast excavating device for removing dirty ballast from under the track and to clean it on another screen arrangement. The cleaned ballast lying on the track is taken up from the ties by an endless conveyor chain and redistributed in the excavated ballast bed portion behind the transverse excavating chain course of the other ballast excavating device, together with the cleaned ballast coming from the other screen arrangement. This installation increases the efficiency of ballast cleaning in an intermittent operation with the aid of three spaced apart ballast excavating devices.
A sand clearing machine for operation in desert regions and known as SRM 500 is described in "Eisenbahntechnische Rundschau," (Railroad Review), Vol. 4, 1980, pp.299/300. This machine is designed to remove sand blown over a track and comprises a sand clearing elevator cantilevered to the front end of the machine. The removed sand is discharged at a track shoulder by a conveyor band arrangement.
Other ballast bed rehabilitation installations of interest are disclosed in U.S. Pat. No. 5,090,483 and Austrian patent No. 235,328.